| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */ |
| 2 | |
| 3 | #ifndef _CRIS_CHECKSUM_H |
| 4 | #define _CRIS_CHECKSUM_H |
| 5 | |
| 6 | #include <asm/arch/checksum.h> |
| 7 | |
| 8 | /* |
| 9 | * computes the checksum of a memory block at buff, length len, |
| 10 | * and adds in "sum" (32-bit) |
| 11 | * |
| 12 | * returns a 32-bit number suitable for feeding into itself |
| 13 | * or csum_tcpudp_magic |
| 14 | * |
| 15 | * this function must be called with even lengths, except |
| 16 | * for the last fragment, which may be odd |
| 17 | * |
| 18 | * it's best to have buff aligned on a 32-bit boundary |
| 19 | */ |
| 20 | unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); |
| 21 | |
| 22 | /* |
| 23 | * the same as csum_partial, but copies from src while it |
| 24 | * checksums |
| 25 | * |
| 26 | * here even more important to align src and dst on a 32-bit (or even |
| 27 | * better 64-bit) boundary |
| 28 | */ |
| 29 | |
| 30 | unsigned int csum_partial_copy_nocheck(const char *src, char *dst, |
| 31 | int len, unsigned int sum); |
| 32 | |
| 33 | /* |
| 34 | * Fold a partial checksum into a word |
| 35 | */ |
| 36 | |
| 37 | extern inline unsigned int csum_fold(unsigned int sum) |
| 38 | { |
| 39 | /* the while loop is unnecessary really, it's always enough with two |
| 40 | iterations */ |
| 41 | |
| 42 | while(sum >> 16) |
| 43 | sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */ |
| 44 | |
| 45 | return ~sum; |
| 46 | } |
| 47 | |
| 48 | extern unsigned int csum_partial_copy_from_user(const char *src, char *dst, |
| 49 | int len, unsigned int sum, |
| 50 | int *errptr); |
| 51 | |
| 52 | /* |
| 53 | * This is a version of ip_compute_csum() optimized for IP headers, |
| 54 | * which always checksum on 4 octet boundaries. |
| 55 | * |
| 56 | */ |
| 57 | |
| 58 | extern inline unsigned short ip_fast_csum(unsigned char * iph, |
| 59 | unsigned int ihl) |
| 60 | { |
| 61 | return csum_fold(csum_partial(iph, ihl * 4, 0)); |
| 62 | } |
| 63 | |
| 64 | /* |
| 65 | * computes the checksum of the TCP/UDP pseudo-header |
| 66 | * returns a 16-bit checksum, already complemented |
| 67 | */ |
| 68 | |
| 69 | extern inline unsigned short int csum_tcpudp_magic(unsigned long saddr, |
| 70 | unsigned long daddr, |
| 71 | unsigned short len, |
| 72 | unsigned short proto, |
| 73 | unsigned int sum) |
| 74 | { |
| 75 | return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); |
| 76 | } |
| 77 | |
| 78 | /* |
| 79 | * this routine is used for miscellaneous IP-like checksums, mainly |
| 80 | * in icmp.c |
| 81 | */ |
| 82 | |
| 83 | extern inline unsigned short ip_compute_csum(unsigned char * buff, int len) { |
| 84 | return csum_fold (csum_partial(buff, len, 0)); |
| 85 | } |
| 86 | |
| 87 | #endif |